Exploring Alternatives to QFT: A Critique of Non-Interacting Quantum Fields

[waterfall]

Before continuing misinterpreting what I really said, please read what I wrote in #201. Thanks.

Thanks. I understood things now more clearly than ever.

I believe with a little fixing, the quantum spin-2 field would be the primary entity and the geometry merely as a result of the symmetry in the math of the quantum field theory.

It's better than believing gravity is only geometry as General Relativity folks love to express.
Therefore I'm more inclined now toward string theory especially M-Theory which may involve what Witten describes as an incredible quantum symmetry where strings are just temporary constructs or a dual bit.

I'm not sure about Loop Quantum Gravity. If it's about geometry and reverse engineering it to get to the quantum parts or spin networks. Then it has less elegance.

 

[waterfall]

And no, GR ist not just the theory of a spin 2 graviton; string theorists know this probably better than anyone. How often needs it to be repeated that gravitons corresponds to "small ripples on a water surface" and not to the whole ocean including vortices etc.

The amount of misconceptions, desinformation and plain nonsense propagated here is really staggering!

In quantum field theory, the quanta like photons and gravitons are just momentum and energy of the fields. Of course you need the entire fields to do the work although what you can measure are simply the photons and gravitons but the fields which you take as the ocean underneath the "small ripples on a water surface" need to be active with the properties it needs.

Now in the case of our spin-2 gravitons discussions. To be sure I understood the concept. Let me explain it to you. What they meant when they say spin-2 field over flat spacetime equaled curved spacetime and gravity is not that spin-2 gravitons is enough to pull off those trick. But the ocean or gravitational fields derived from a quantum gravity has the properties and right coupling to pull of the gravity act. Then the spin-2 gravitons are just manifestation of this hidden gravitational fields. Therefore to avoid confusion. I think the proper things to say is instead of:

"Spin 2 gravitons + flat spacetime = General Relativity". One must say this:

"Spin 2 gravitons (with underlying gravitational field produced from excitations of strings or LQG or others) + flat spacetime = General Relativity."

Are we clear on this now. You guys used the former descriptons all throughout hence you confused even others like "surprised". Right?

 

[waterfall]

In post #99 a week ago:

Strange idea! Who told you that? Do the gravitons also make it appear that space is expanding? And expanding at different rates at different times and places? Do they make the expansion appear accelerate by various amounts, but it isn't really accelerating?

Sounds like someone sold you a load of bunkum, WF.

We had a long detour on string theory and spin-2 graviton thing because I was asking Marcus above (in post #98) if Loop Quantum Gravity was also about spin-2 graviton on flat spacetime and up to now it isn't answered because Marcus reactions to this spin-2 graviton idea is the above.

Well. So how do spin-2 gravitons (plus gravity fields) over flat spacetime explains Big Bang expansion? I guess we can consider the spin-2 fields as unique in that the fields can expand. Remember the Inflaton is also a field.. so it fills the gravity fields with inflatons expanding the fields with the effect as like producing spacetime curvature (but not really). Isn't it?

About Loop Quantum Gravity. So we can also consider it as spin networks producing the right coupling of gravity and hence can also be consider as having graviton spin-2 field over flat spacetime. Meaning spacetime only appears curved in LQG but not really curved?? This was what I was asking Marcus prior to his reply above whether one can consider LQG as like String theory where it is about spin-2 gravity fields over flat spacetime with the curvature geometry as not really a priori. But Marcus, like fellow poster surprised, misunderstood the concept as I didn't add the gravity field (behind spin 2) idea so didn't answer it. So let me ask this again now so someone can answer this LQG question above and we can close this thread clean. Thanks.